1. Field of the Invention
The present invention concerns a parts handling device intended for loading and unloading sheet metal coils between a storage area and a machine, for instance a reel, whereas this device is designed to be mounted on a handling apparatus having at least a fixed mast and a table moving vertically along the mast and equipped with forks.
2. Description of the Related Art
The invention applies more specifically to the handling of sheet metal coils, commonly called xe2x80x9ccoilsxe2x80x9d, with a width below or equal to approximately 700 mm, but it can naturally be extended to other heavy, bulky and difficult to handle products.
These sheet metal coils are generally stored flat by the cutting companies on pallets or on planks assembled so as to make a transport support. They are stacked each upon another and separated by wood laths with variable sections, for instance 25 to 50 mm. This coils-pallet set is stored for instance in a storage frame, transported on a traditional way by a fork lift truck and placed close to the reel, which is, in this very case, a horizontal-shaft reel.
There are several techniques allowing loading such a coil on the chuck of the reel. A first technique consists of a single-rail girder equipped with a hoisting gear that allows, thanks to a sling, gripping the coil, changing its axis, i.e. tilting it by 90xc2x0 in order to bring it from the vertical axis to the horizontal axis and mounting it on the chuck of the reel. This technique requires several manual interventions of the operator, which are often dangerous due to possible shocks and to the fact that the coil, which has been slit, may have sharp edges.
A second technique, which is the most widely used one, consists in gripping the coil directly with one of the forks of the lift truck. This operation requires much skill on the part of the lift truck driver, with the risk that the coil slips away from the fork and falls on the floor.
A third technique consists of equipping a lift truck with a specific gripping device, as described in the publications U.S. Pat. No. 3,991,893 and GB-A-1 260 474. Nevertheless, with this solution, the lift truck cannot be used any more for any other task, since the gripping device remains mounted permanently on said truck. This means that the operator cannot use the same lift truck to move the coil pallets and to load the coils on the reel.
Furthermore, in this very specific technical branch, most of the sheet metal coil users impose their suppliers a winding direction for the coils. For instance, the winding direction of the coil is considered correct for feeding the reel and the manufacturing line located downstream, if the underside of the coil supplied lying corresponds to the side located towards the chuck of the reel. Yet the suppliers do not always respect the coiling direction asked for by their customers. It is thus necessary to turn the coil by half a turn when it is in lifted position, with its axis horizontal. But this operation is dangerous for the operator because of the weight of the coil and the risk of the coil falling down.
The aim of the present invention is to offer a technical solution allowing one single operator, driving one single and standard apparatus such as a fork lift truck equipped with a specific handling device, to carry out the stacking of the coil pallets, the transport of the pallets close to the reel and the loading and unloading of the coils on the reel, without manual handling, in all safety for the operator and the material, and in a short time.
Another aim of the invention is to arrange the specific handling device on said lift truck in such a way that the latter can work normally with all its capacities and functions when the handling device is not in operative position.
An additional aim of the invention is to have the possibility to choose the lifting direction of the coils, in order to turn them if necessary, in particular if they are positioned upside down on the pallet, with the correct coil side on the top.
To these purposes, the invention concerns a device comprising at least a support designed to be mounted on the table of the handling apparatus in order to allow using said handling device, at least a member for gripping a coil to be handled, a frame connecting the gripping member with said support and control means, whereas the gripping member is articulated in relation to said frame on a first pivoting pin and the frame is articulated in relation to said support on a second pivoting pin, whereas the first and second pivoting pins are parallel and distant of each another in such a way that, when using the handling device, whereas the support is mounted on the table of the handling apparatus, the control means act from said support upon the frame in order to tilt it on the second pivoting pin between an operative position, in which the gripping member extends from the first pivoting pin between the forks of the handling apparatus so as to allow the gripping member to hang up the coil to be handled below the forks of the handling apparatus, and an inoperative position, in which both the gripping member and the frame are lifted above the support in order to be placed inside the mast of the handling apparatus, so as to set the forks free.
The gripping member has preferably a L-shaped hook, whose long leg is firmly attached to a lifting beam arranged parallel and on the end opposite to the small leg, and designed to rest on said forks of the handling apparatus when the handling device is in operative position, whereas the small leg is located at a lower level than the level of said forks.
The hook is advantageously designed so as to handle coils having a width at the most equal to twice the useful length of the small leg and a radial thickness at the most equal to the length of the long leg. The small leg of the hook has preferably at its end a thickness smaller than the section of the laths placed between two coils lying upon another on a pallet.
In a preferred embodiment, the lifting beam has, at each fork of the lift truck, two supporting points with an interval i between them and defining a supporting plane, whereas at least one of the supporting points can be adjusted in height.
In this embodiment, the first pivoting pin between the gripping member and the frame can be located vertically above the centre of gravity of said gripping member so as to position the hook vertically and the supporting plane horizontally, whatever the position of said frame.
The interval i between the supporting points on a same fork is preferably at least equal to the useful length of the small hook leg. This way, the vertical line passing through the centre of gravity of the coil to be handled when it is held by the hook passes between these two supporting points, which allows stabilising and stiffening in space said gripping member when it is in operative position.
The frame may include two parallel levers connected by at least one crossbeam, but it may also be designed differently.
In the preferred embodiment, the control means include at least a jack coupled on one side with the support by means of a third pivoting pin constituting a fixed point and, on the other side, with the frame by means of a fourth pivoting pin constituting a mobile point.
This fourth pivoting pin is, for example, made up of a crossbeam of said frame, located away from the second pivoting pin provided between the frame and the support, in order to create a turning moment on said frame.
This frame can include a locking element designed to lock the gripping member in the inoperative position.
The first and second pivoting pins provided respectively between the gripping member and the frame and between the frame and the support are distant by a distance at least equal to the length of the long hook leg.
In an embodiment variant, the lifting beam includes, at each fork of the lift truck, at least one supporting area at the front of said hook.
In this variant, the frame includes two parallel rods connected with each another by their pivoting pins.
The control means include preferably at least one jack coupled on one side with the support by means of a third pivoting pin constituting a fixed point and, on the other side, with the lifting beam by means of a fourth pivoting pin constituting a mobile point, so that the four pivoting pins define a deformable polygon.
The frame may include at least a tilting stop designed to abut against the lifting beam when the latter is in the tilting phase between the operative and the inoperative position.
In this embodiment, the gripping means include advantageously a rotation device of said hook designed to turn it on a rotation axis between at least a front and a rear position.
This rotation device comprises, for example, at least a jack firmly attached to the lifting beam and whose rod is firmly attached to a rack driving a pinion firmly attached to said hook.
In certain cases, the gripping member may include two hooks arranged in parallel and oriented in the same direction or in opposite directions.
The invention also concerns a handling apparatus having at least a fixed mast and a table moving vertically along the mast and bearing forks, characterised in that it includes a parts handling device as defined above.